Novak served up a storm for Rafa

"Is something unbelievable how he returns, no? His return probably is one of the best of the history. I never played against a player who's able to return like this. Almost every time." Thus spoke Rafael Nadal after the epic Australian Open final against Novak Djokovic. There wasn't a whole lot to separate the two giants of the game after 5 hours and 53 minutes, but one telling stat was the percentage of points won on second serve: Djokovic won 63%, Nadal 45%.

In fact, 63% is exactly the percentage of points that Nadal won off his second serve in his semi-final against Roger Federer - it's the one stat that eloquently explains the difference between the two match-ups. The single-handed backhand is an obvious liability for Federer against Nadal, but the way he deals with Nadal's second serve is another. Federer realises the necessity to take charge, but his methods are far riskier when he tries to do so: on the ad court, he runs around his backhand to rip a forehand, but in doing so he opens up the court completely for Nadal, which means anything less than a perfect shot isn't enough. Nadal's also smartened up to this approach by going down the middle to catch Federer off guard. And when Federer doesn't go ultra-aggressive on the return, Nadal is ready to dictate the point with his fiendish groundies.

Djokovic's approach is far more measured, and far more effective. From either flank, he hits the ball hard and deep, but usually down the middle of the court. It gives Nadal no time to react, and little angles to work with. Nadal thus starts the rallies on the defensive, and Djokovic's solidity and explosiveness off either flank means he wins most of those rallies.

It isn't as if Nadal didn't alter his game in the Australian Open final to stop that six-match losing streak. The first serve attacked Djokovic's body far more often than in the past, and it helped him win more points than in the US Open final last year: then he'd won just 52% of his first-serve points; here it went up to 66%. But the second-serve points won remained dismal: 42% in the US Open final, 45% here.

Overall in this final, Djokovic won 17 more points than Nadal (193 to 176); had Nadal's second serve won him an equal percentage of points as Djokovic's, that difference would have reduced to 5. Arguably, second-serve numbers was the single biggest differentiator in the stats between the two players. Nadal served one ace and two double-faults more, while Djokovic won two percentage points more on his first serve (68% to 66%). Djokovic had 13 more winners - but then you expect him to force the issue more often - while Nadal's 71 unforced errors was the other surprise in terms of numbers.

Clearly, Djokovic's return of serve has been a vital aspect of matches between these two. In their last six meetings, Nadal hasn't won more than 45% of the points on his second serve in any match - in the 6-4 6-4 defeat in the Rome Masters last year, that percentage had dropped to a shocking 25%.

Those low percentages means Djokovic has had several looks at break-point opportunities in these matches: he had 20 chances in this final, and 27 in the US Open last year. At Wimbledon he had six, but he didn't need many more since he converted five of those. In these last seven matches, Djokovic has had 93 opportunities to break serve, compared to 48 for Nadal. Unlike the Federer-Nadal match-ups, it isn't as if one player struggles to convert those opportunities: Nadal's conversion rate in these seven matches is 48%, compared to Djokovic's 43%. However, Djokovic has created so many more break-point opportunities - an average of 13 per match - that he has broken serve far more often than Nadal has (three per match). In the earlier 21 matches between them (excluding their Davis Cup and Olympics matches), Djokovic had only managed six break-point opportunities per match (though the conversion rate in those matches was also a healthy 41%). In 14 of those 21 matches, Nadal won 50% or more of his second-serve points.

However, returning second serves better has given Djokovic many more chances to break serve. Add that to a conversion rate that has always been impressive, and Djokovic has conjured up the perfect answer to solve the Nadal puzzle.